1. FIELD OF THE INVENTION
The present invention relates to a vehicle body height control system or more particularly, to a vehicle body height control system with an improved riding feeling or performance during the process of vehicle body height adjustment. The system of this invention is hereinafter referred to simply as the vehicle height control system.
The present invention is applicable to a vehicle height control system in which a vehicle height adjuster is arranged for each wheel (one for each of the front wheels and one for either each of the rear wheels or all of the rear wheels) to control the distance between each wheel and the vehicle body, namely, the vehicle body height, with each vehicle height adjuster independently.
2. DESCRIPTION OF THE PRIOR ART
A vehicle height control system has been proposed conventionally, in which, in order to obtain a desired vehicle height in response to the number of passengers, the amount of loads, the running conditions and the road surface conditions, a plurality of vehicle height adjusters are provided to control the vehicle body height at a target level.
In such a conventional vehicle height control system, an attempt to extend or contract all the vehicle height adjusters by the same height would necessitate different extension or contraction rates (different adjusting rates) for the respective vehicle height adjusters because of the differences in the loads on or in the spring characteristics of the respective vehicle height adjusters.
This variation in the adjusting rate causes an unstable slant of the vehicle body under adjustment and undesirably makes the driver and passengers (hereinafter simply called "the driver") anxious.
This problem is attributable to the fact that each vehicle height adjuster is extended or contracted regardless of the adjusting rate of the other adjusters.
The present invention is intended to obviate this disadvantage of the prior art.